Olaparib‐Based Photoaffinity Probes for PARP‐1 Detection in Living Cells

Abstract

The poly‐ADP‐ribose polymerase (PARP) is a protein from the family of ADP‐ribosyltransferases that catalyzes polyadenosine diphosphate ribose (ADPR) formation in order to attract the DNA repair machinery to sites of DNA damage. The inhibition of PARP activity by olaparib can cause cell death, which is of clinical relevance in some tumor types. This demonstrates that quantification of PARP activity in the context of living cells is of great importance. In this work, we present the design, synthesis and biological evaluation of photo‐activatable affinity probes inspired by the olaparib molecule that are equipped with a diazirine for covalent attachment upon activation by UV light and a ligation handle for the addition of a reporter group of choice. SDS‐PAGE, western blotting and label‐free LC‐MS/MS quantification analysis show that the probes target the PARP‐1 protein and are selectively outcompeted by olaparib; this suggests that they bind in the same enzymatic pocket. Proteomics data are available via ProteomeXchange with identifier PXD018661.

Privileged Scaffolds for Potent and Specific Inhibitors of Mono-ADP-Ribosylating PARPs

“…In the PARPs field, many poly-ARTs inhibitors have been exploited as tools, with most of them represented by radiolabelled compounds, which are also emerging as promising tumor imaging agents [127][128][129][130]. On the contrary, a very few examples of clickable compounds are known [131][132][133][134].…”

Chemistry for the Identification of Therapeutic Targets: Recent Advances and Future Directions

“…Both objectives, drug repurposing and off‐target identification share a common need: the availability of compounds able to capture, visualize, and identify all the targets of a given drug. In this regard, and as detailed in the former sections, both ABPs and AfBPs have contributed to profile the targets of marketed NSAIDs, [51] or anticancer compounds such as olaparib [48] or ingenol mebutate [47] …”

“…Another important small molecule with antitumor activity is olaparib, a poly‐ADP‐ribose polymerase (PARP) inhibitor approved for the treatment of ovarian cancer and certain types of breast tumors. Recently disclosed olaparib AfBPs (Figure 8C) allow for the visualization of this enzyme in living cells and the identification of some of its off‐targets [48] . Several histone deacetylase (HDAC) inhibitors have been approved by the FDA for the treatment of T cell lymphoma and multiple myeloma.…”

“…Recently disclosed olaparib AfBPs ( Figure 8C) allow for the visualization of this enzyme in living cells and the identification of some of its off-targets. [48] Several histone deacetylase (HDAC) inhibitors have been approved by the FDA for the treatment of T cell lymphoma and multiple myeloma. Hence, the availability of chemical probes that make possible the visualization of the different HDAC isoforms, the determination of selectivity profiles, and the identification of their protein partners has gained a growing relevance in the field.…”

Quinone Methide Based Self‐Immobilizing Molecular Fluorescent Probes for In Situ Imaging of Enzymes

“…An alternative strategy to minimize product diffusion is to couple the probe with target enzyme and simultaneously release the fluorescence for tracing. Based on this principle, self‐immobilizing fluorogenic imaging agents including covalent inhibitor‐derived probes, [11] photo‐crosslinking affinity‐based probes, [12] quinone methide (QM)‐based probes [13] and ligand‐directed traceless labeling‐based probes [14] have been developed for in situ imaging enzyme with high resolution and long time. Covalent inhibitor‐based probes show extremely high selectivity and binding efficiency, but inactivate the enzymes [15] .…”